Aryl mercury salts of chloro substituted phencxyacetic acids



Patented Feb. 19, 1952 ARYL MERCURY SALTS OF CHLORO SUB STITUTED'PHENOXYACETIC ACIDS Paul A. Sartorett'o, New York N. Y. assignor to W.A. Cleary Corporation, a corporation of New Jersey No Drawing. Originalapplication March' 21,

1947, Serial No. 736,412.

Divided and this application February 5, 1951, Serial No. 209,511

This invention relates to a method of killing weeds in an active stateof growth and to the materials that are used in killing the weeds.

This application is a division of my copending application Serial No.736,412, filed March 21, 1947, now Patent No. 2,545,431.

Various types of weed killers have been proposed and are now being used.These materials have a selective action in that they will kill weeds butwill not harm the grass and other useful plants. I have discovereda moreefficient weed killer that kills and inhibits the further growth of agreater variety of weeds than was true with former weed killingmaterials. The new weed killers of this invention are aryl mercury saltsof 2,4-dichlorophenoxy acetic acid, 2,5- dichlorophenoxy acetic acid,and 2,4,5-trichlorophenoxy acetic acid. The new salts are reactionproducts of aryl mercury compounds and the above acids.

The new weed killing salts are used in a carrier. This carrier can beeither a solvent, a water-soluble solvent for the salt and water, or aninert powder such as finely-divided clays, calcium carbonate, and thelike. The water-soluble solvents for the salts may be alcohols,preferably the lower aliphatic alcohols, formamide, carbitol, and thelike. The salts are preferably used in a concentration of about one partof the salt per 1,000 to 80,000 parts of a carrier. The

stronger solutions may be used in a single treatment, but this is notrecommended as it may kill all plant growths in the treated area. Thepreferred way of using the weed killers is to apply them at intervals toa given area under treatment. This destroys the weeds without harmingthe grass and prevents new growths of weeds. The weed killers may beapplied in a concentration of ten gallons per 1,000 square feet atintervals of five to thirty days for about three months. This will serveto kill any weeds that may be present and prevent the growth of otherweeds.

The salts are preferably prepared by using equal molar proportions of anaryl mercury salt, preferably of an organic acid, and either2,4-dichlorophenoxy acetic acid, 2,5-dichlorophenoxy acetic acid, or2,4,5-trichlorophenoxy acetic acid.

The new salts are preferably used in conjunction with boric acid and analkanolamine such as an ethanolamine. These materials make the solutionsof the salt more stable and increases their potency. The boric acid andalkanolamine are preferably used in such concentrations that there is atleast one-third molar weight of the 8 Claims. (01. 260-434) 2 boric acidto each hydroxyl equivalent weight of the amine. It is believed that theboric acid and the alkanolamine react to form an alkanolamine borate.The boric acid and alkanolamine may be used in any concentration desiredwith relation to the weed killing salts so as to provide an excess ofone or the other. It is preferred, however, that the concentration beapproximately two moles of alkanolamine borate ester to one mole of thearyl mercury salt.

When the aryl mercury salt is used in solution in combination with boricacidv and an alkanolamine, it is preferred that the solution have a pHof from about 7.0 to 9.5. If the pH within this range,-,the..solution ismore stable. Excellent stability has been obtained when the pH is withinthe range of between '7 and 8 and consequently this is the preferredrange. In actual practice apI-I as near 7.5 as possible is desired.

The new salts can be prepared by mixing the above aryl mercury compoundand the acid in the cold. When these reactants are permitted to standunder ordinary atmospheric conditions and at room temperature the newsalt is formed in a matter of two or. three: days. This reaction takesplace either in the container in which the reactants are mixed or afterthe reactants have been applied to the Weeds if the reactants areapplied to the weeds before the reaction in the container has gonetocompletion.

The following examples illustrate the invention:

Example I.One mol of 2,-4-dichlorophenoxy acetic acid Was mixed into onemol of phenylmercuric acetate to form the phenylmercuric salt of2,4-dichlorophenoxy acetic acid. This compound was then dissolved inethyl alcohol to provide a solution that could be used for weed killing.

Example II .-One mol of 2,4-dichlorophenoxy acetic acid was mixed intoone mol of phenylmercuric acetate to form the phenyl mercuric salt of2,4-dichlorophenoxy acetic acid. This was then mixed with the reactionproduct prepared by warming A; mol of boric acid with one mol ofmonoethanolamine until the boric acid is completely dissolved. Themixture was then dissolved in ethyl alcohol to provide a solution thatcould be used for weed killing.

Ewample III.-The same procedure as in Example I was followed but herethe acid compound was 2,5-dichlorophenoxy' acetic acid.

Example IV.-The same procedure as in Ex ample I was followed except thathere the acid was 2,4,5-trichlorophenoxy acetic acid.

In any of the above examples any of the chlorophenoxy acids may be usedin place of the one specifically mentioned.

Although the aryl mercury salt is preferably reacted with the acid inapproximately equal molar proportions, more or less of either of thereacting materials may be used to provide an excess of that material, ifdesired.

Having described my invention as related to the embodiments set outherein, it is my intention that the invention be not limited by any ofthe details of description unless otherwise specified, but rather beconstructed broadly within its spirit and scope as set out in theaccompanying claims.

I claim:

1. The new compound: the aryl mercury salt of an acid of the classconsisting of 2,4-dichlorophenoxy acetic acid, 2,5-dichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxy acetic acid having thestructural formula AHgOHZCHnOB 0 Omoomoe wherein B is a member of theclass consisting of 2,4-dichlorophenyl groups, 2,5-dichlorophenylgroups, and 2,4,5-trichlorophenyl groups.

3. The new compound: the: aryl mercury salt of 2,4-dichlorophenoxyacetic acid having the structural formula 0 AHgO cum-O-m wherein A is anaryl group.

r 4. The new compound: the aryl mercury salt of 2,5-dichlorophenoxyacetic acid having the structural formula 0 Wang wherein A is anarylgroup.

5. The new compound: the aryl mercury salt of 2,4,5-trichlorophenoxyacetic acid having the structural formula 0 AmOaMQa wherein A isan arylgroup.

6. The new compound: the phenyl mercury salt of 2,4-dichlorophenoxyacetic acid having the structural formula 7. The new compound: thephenyl mercury salt of 2,5-dichlorophenoxy acetic acid having thestructural formula i uotas? 8. The new compound: the phenyl mercury saltof 2,4,5-trichlorophenoxy acetic acid having the structural formula 01 Wl Omooomo-O-m PAUL A. SARTORET'I'O.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. THE NEW COMPOUND: THE ARYL MERCURY SALT OF AN ACID OF THE CLASSCONSISTING OF 2,4-DICHLOROPHENOXY ACETIC ACID, 2,5-DICHLOROPHENOXYACETIC ACID, AND 2,4,5-TRICHLOROPHENOXY ACETIC ACID HAVING THESTRUCTURAL FORMULA